For example, a shoe having a non-slip member on a shoe sole as disclosed in Japanese Patent Laid-Open No. 01-310601 (the first patent document) is publicly known.
Such non-slip member is formed by attaching a lot of resin or rubber non-slip protuberances to a base fabric such as knitted fabric, woven fabric or non-woven fabric (the second patent documents, the third patent document).
A shoe having a cup sole that rolls upwards at its side faces is also publicly known (the fourth patent document).
The first patent document: Japanese Patent Laid-Open No. 01-310601 (FIG. 6, FIG. 7)
The second patent document: Japanese Patent Laid-Open No. 06-000826 (Abstract)
The third patent document: U.S. Pat. No. 6,255,235 (claim 1, FIG. 1 (a), FIG. 1 (b))
The fourth patent document: Japanese Patent Laid-Open No. 05-123204 (FIG. 8)
For indoor shoes used for wrestling, boxing, sitting volleyball and the like, contact sensation of the sole of the foot with the floor face is important and thus high gripping characteristic, high flexibility and lightness in weight are required. For this reason, the above-mentioned non-slip member is provided on the shoe sole or side faces of the shoe.
In these sports, a large load is often concentrated on small protuberances over and over again. The load is liable to be concentrated especially on corner portions between the bottom face and the side faces of the shoe. Thus, the non-slip member requires high durability.